[ViewVC] Diff of: cvs/AnyEvent-MP/MP.pm

Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.71 by root, Sun Aug 30 19:52:56 2009 UTC vs.
Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC

…		…
1	=head1 NAME	1	=head1 NAME
2		2
3	AnyEvent::MP - multi-processing/message-passing framework	3	AnyEvent::MP - erlang-style multi-processing/message-passing framework
4		4
5	=head1 SYNOPSIS	5	=head1 SYNOPSIS
6		6
7	use AnyEvent::MP;	7	use AnyEvent::MP;
8		8
9	$NODE # contains this node's noderef	9	$NODE # contains this node's node ID
10	NODE # returns this node's noderef	10	NODE # returns this node's node ID
11	NODE $port # returns the noderef of the port
12		11
13	$SELF # receiving/own port id in rcv callbacks	12	$SELF # receiving/own port id in rcv callbacks
14		13
15	# initialise the node so it can send/receive messages	14	# initialise the node so it can send/receive messages
16	initialise_node;	15	configure;
17		16
18	# ports are message endpoints	17	# ports are message destinations
19		18
20	# sending messages	19	# sending messages
21	snd $port, type => data...;	20	snd $port, type => data...;
22	snd $port, @msg;	21	snd $port, @msg;
23	snd @msg_with_first_element_being_a_port;	22	snd @msg_with_first_element_being_a_port;
24		23
25	# creating/using ports, the simple way	24	# creating/using ports, the simple way
26	my $simple_port = port { my @msg = @_; 0 };	25	my $simple_port = port { my @msg = @_ };
27		26
28	# creating/using ports, tagged message matching	27	# creating/using ports, tagged message matching
29	my $port = port;	28	my $port = port;
30	rcv $port, ping => sub { snd $_[0], "pong"; 0 };	29	rcv $port, ping => sub { snd $_[0], "pong" };
31	rcv $port, pong => sub { warn "pong received\n"; 0 };	30	rcv $port, pong => sub { warn "pong received\n" };
32		31
33	# create a port on another node	32	# create a port on another node
34	my $port = spawn $node, $initfunc, @initdata;	33	my $port = spawn $node, $initfunc, @initdata;
35		34
		35	# destroy a prot again
		36	kil $port; # "normal" kill
		37	kil $port, my_error => "everything is broken"; # error kill
		38
36	# monitoring	39	# monitoring
37	mon $port, $cb->(@msg) # callback is invoked on death	40	mon $localport, $cb->(@msg) # callback is invoked on death
38	mon $port, $otherport # kill otherport on abnormal death	41	mon $localport, $otherport # kill otherport on abnormal death
39	mon $port, $otherport, @msg # send message on death	42	mon $localport, $otherport, @msg # send message on death
		43
		44	# temporarily execute code in port context
		45	peval $port, sub { die "kill the port!" };
		46
		47	# execute callbacks in $SELF port context
		48	my $timer = AE::timer 1, 0, psub {
		49	die "kill the port, delayed";
		50	};
40		51
41	=head1 CURRENT STATUS	52	=head1 CURRENT STATUS
42		53
43	bin/aemp - stable.	54	bin/aemp - stable.
44	AnyEvent::MP - stable API, should work.	55	AnyEvent::MP - stable API, should work.
45	AnyEvent::MP::Intro - uptodate, but incomplete.	56	AnyEvent::MP::Intro - explains most concepts.
46	AnyEvent::MP::Kernel - mostly stable.	57	AnyEvent::MP::Kernel - mostly stable API.
47	AnyEvent::MP::Global - stable API, protocol not yet final.	58	AnyEvent::MP::Global - stable API.
48
49	stay tuned.
50		59
51	=head1 DESCRIPTION	60	=head1 DESCRIPTION
52		61
53	This module (-family) implements a simple message passing framework.	62	This module (-family) implements a simple message passing framework.
54		63
56	on the same or other hosts, and you can supervise entities remotely.	65	on the same or other hosts, and you can supervise entities remotely.
57		66
58	For an introduction to this module family, see the L<AnyEvent::MP::Intro>	67	For an introduction to this module family, see the L<AnyEvent::MP::Intro>
59	manual page and the examples under F<eg/>.	68	manual page and the examples under F<eg/>.
60		69
61	At the moment, this module family is a bit underdocumented.
62
63	=head1 CONCEPTS	70	=head1 CONCEPTS
64		71
65	=over 4	72	=over 4
66		73
67	=item port	74	=item port
68		75
69	A port is something you can send messages to (with the C<snd> function).	76	Not to be confused with a TCP port, a "port" is something you can send
		77	messages to (with the C<snd> function).
70		78
71	Ports allow you to register C<rcv> handlers that can match all or just	79	Ports allow you to register C<rcv> handlers that can match all or just
72	some messages. Messages send to ports will not be queued, regardless of	80	some messages. Messages send to ports will not be queued, regardless of
73	anything was listening for them or not.	81	anything was listening for them or not.
74		82
…		…
85		93
86	Nodes are either public (have one or more listening ports) or private	94	Nodes are either public (have one or more listening ports) or private
87	(no listening ports). Private nodes cannot talk to other private nodes	95	(no listening ports). Private nodes cannot talk to other private nodes
88	currently.	96	currently.
89		97
90	=item node ID - C<[a-za-Z0-9_\-.:]+>	98	=item node ID - C<[A-Z_][a-zA-Z0-9_\-.:]*>
91		99
92	A node ID is a string that uniquely identifies the node within a	100	A node ID is a string that uniquely identifies the node within a
93	network. Depending on the configuration used, node IDs can look like a	101	network. Depending on the configuration used, node IDs can look like a
94	hostname, a hostname and a port, or a random string. AnyEvent::MP itself	102	hostname, a hostname and a port, or a random string. AnyEvent::MP itself
95	doesn't interpret node IDs in any way.	103	doesn't interpret node IDs in any way.
…		…
99	Nodes can only talk to each other by creating some kind of connection to	107	Nodes can only talk to each other by creating some kind of connection to
100	each other. To do this, nodes should listen on one or more local transport	108	each other. To do this, nodes should listen on one or more local transport
101	endpoints - binds. Currently, only standard C<ip:port> specifications can	109	endpoints - binds. Currently, only standard C<ip:port> specifications can
102	be used, which specify TCP ports to listen on.	110	be used, which specify TCP ports to listen on.
103		111
104	=item seeds - C<host:port>	112	=item seed nodes
105		113
106	When a node starts, it knows nothing about the network. To teach the node	114	When a node starts, it knows nothing about the network. To teach the node
107	about the network it first has to contact some other node within the	115	about the network it first has to contact some other node within the
108	network. This node is called a seed.	116	network. This node is called a seed.
109		117
110	Seeds are transport endpoint(s) of as many nodes as one wants. Those nodes	118	Apart from the fact that other nodes know them as seed nodes and they have
		119	to have fixed listening addresses, seed nodes are perfectly normal nodes -
		120	any node can function as a seed node for others.
		121
		122	In addition to discovering the network, seed nodes are also used to
		123	maintain the network and to connect nodes that otherwise would have
		124	trouble connecting. They form the backbone of an AnyEvent::MP network.
		125
111	are expected to be long-running, and at least one of those should always	126	Seed nodes are expected to be long-running, and at least one seed node
112	be available. When nodes run out of connections (e.g. due to a network	127	should always be available. They should also be relatively responsive - a
113	error), they try to re-establish connections to some seednodes again to	128	seed node that blocks for long periods will slow down everybody else.
114	join the network.
115		129
116	Apart from being sued for seeding, seednodes are not special in any way -	130	=item seeds - C<host:port>
117	every public node can be a seednode.	131
		132	Seeds are transport endpoint(s) (usually a hostname/IP address and a
		133	TCP port) of nodes that should be used as seed nodes.
		134
		135	The nodes listening on those endpoints are expected to be long-running,
		136	and at least one of those should always be available. When nodes run out
		137	of connections (e.g. due to a network error), they try to re-establish
		138	connections to some seednodes again to join the network.
118		139
119	=back	140	=back
120		141
121	=head1 VARIABLES/FUNCTIONS	142	=head1 VARIABLES/FUNCTIONS
122		143
…		…
134		155
135	use AE ();	156	use AE ();
136		157
137	use base "Exporter";	158	use base "Exporter";
138		159
139	our $VERSION = $AnyEvent::MP::Kernel::VERSION;	160	our $VERSION = 1.24;
140		161
141	our @EXPORT = qw(	162	our @EXPORT = qw(
142	NODE $NODE *SELF node_of after	163	NODE $NODE *SELF node_of after
143	initialise_node	164	configure
144	snd rcv mon mon_guard kil reg psub spawn	165	snd rcv mon mon_guard kil psub peval spawn cal
145	port	166	port
146	);	167	);
147		168
148	our $SELF;	169	our $SELF;
149		170
…		…
155		176
156	=item $thisnode = NODE / $NODE	177	=item $thisnode = NODE / $NODE
157		178
158	The C<NODE> function returns, and the C<$NODE> variable contains, the node	179	The C<NODE> function returns, and the C<$NODE> variable contains, the node
159	ID of the node running in the current process. This value is initialised by	180	ID of the node running in the current process. This value is initialised by
160	a call to C<initialise_node>.	181	a call to C<configure>.
161		182
162	=item $nodeid = node_of $port	183	=item $nodeid = node_of $port
163		184
164	Extracts and returns the node ID from a port ID or a node ID.	185	Extracts and returns the node ID from a port ID or a node ID.
165		186
166	=item initialise_node $profile_name, key => value...	187	=item configure $profile, key => value...
		188
		189	=item configure key => value...
167		190
168	Before a node can talk to other nodes on the network (i.e. enter	191	Before a node can talk to other nodes on the network (i.e. enter
169	"distributed mode") it has to initialise itself - the minimum a node needs	192	"distributed mode") it has to configure itself - the minimum a node needs
170	to know is its own name, and optionally it should know the addresses of	193	to know is its own name, and optionally it should know the addresses of
171	some other nodes in the network to discover other nodes.	194	some other nodes in the network to discover other nodes.
172		195
173	This function initialises a node - it must be called exactly once (or	196	This function configures a node - it must be called exactly once (or
174	never) before calling other AnyEvent::MP functions.	197	never) before calling other AnyEvent::MP functions.
175		198
176	The first argument is a profile name. If it is C<undef> or missing, then	199	=over 4
177	the current nodename will be used instead (i.e. F<uname -n>).
178		200
		201	=item step 1, gathering configuration from profiles
		202
179	The function first looks up the profile in the aemp configuration (see the	203	The function first looks up a profile in the aemp configuration (see the
180	L<aemp> commandline utility). the profile is calculated as follows:	204	L<aemp> commandline utility). The profile name can be specified via the
		205	named C<profile> parameter or can simply be the first parameter). If it is
		206	missing, then the nodename (F<uname -n>) will be used as profile name.
181		207
		208	The profile data is then gathered as follows:
		209
182	First, all remaining key => value pairs (all of which are conviniently	210	First, all remaining key => value pairs (all of which are conveniently
183	undocumented at the moment) will be used. Then they will be overwritten by	211	undocumented at the moment) will be interpreted as configuration
184	any values specified in the global default configuration (see the F<aemp>	212	data. Then they will be overwritten by any values specified in the global
185	utility), then the chain of profiles selected, if any. That means that	213	default configuration (see the F<aemp> utility), then the chain of
		214	profiles chosen by the profile name (and any C<parent> attributes).
		215
186	the values specified in the profile have highest priority and the values	216	That means that the values specified in the profile have highest priority
187	specified via C<initialise_node> have lowest priority.	217	and the values specified directly via C<configure> have lowest priority,
		218	and can only be used to specify defaults.
188		219
189	If the profile specifies a node ID, then this will become the node ID of	220	If the profile specifies a node ID, then this will become the node ID of
190	this process. If not, then the profile name will be used as node ID. The	221	this process. If not, then the profile name will be used as node ID. The
191	special node ID of C<anon/> will be replaced by a random node ID.	222	special node ID of C<anon/> will be replaced by a random node ID.
		223
		224	=item step 2, bind listener sockets
192		225
193	The next step is to look up the binds in the profile, followed by binding	226	The next step is to look up the binds in the profile, followed by binding
194	aemp protocol listeners on all binds specified (it is possible and valid	227	aemp protocol listeners on all binds specified (it is possible and valid
195	to have no binds, meaning that the node cannot be contacted form the	228	to have no binds, meaning that the node cannot be contacted form the
196	outside. This means the node cannot talk to other nodes that also have no	229	outside. This means the node cannot talk to other nodes that also have no
197	binds, but it can still talk to all "normal" nodes).	230	binds, but it can still talk to all "normal" nodes).
198		231
199	If the profile does not specify a binds list, then a default of C<*> is	232	If the profile does not specify a binds list, then a default of C<*> is
200	used.	233	used, meaning the node will bind on a dynamically-assigned port on every
		234	local IP address it finds.
201		235
		236	=item step 3, connect to seed nodes
		237
202	Lastly, the seeds list from the profile is passed to the	238	As the last step, the seeds list from the profile is passed to the
203	L<AnyEvent::MP::Global> module, which will then use it to keep	239	L<AnyEvent::MP::Global> module, which will then use it to keep
204	connectivity with at least on of those seed nodes at any point in time.	240	connectivity with at least one node at any point in time.
205		241
206	Example: become a distributed node listening on the guessed noderef, or	242	=back
207	the one specified via C<aemp> for the current node. This should be the	243
		244	Example: become a distributed node using the local node name as profile.
208	most common form of invocation for "daemon"-type nodes.	245	This should be the most common form of invocation for "daemon"-type nodes.
209		246
210	initialise_node;	247	configure
211		248
212	Example: become an anonymous node. This form is often used for commandline	249	Example: become an anonymous node. This form is often used for commandline
213	clients.	250	clients.
214		251
215	initialise_node "anon/";	252	configure nodeid => "anon/";
216		253
217	Example: become a distributed node. If there is no profile of the given	254	Example: configure a node using a profile called seed, which si suitable
218	name, or no binds list was specified, resolve C<localhost:4044> and bind	255	for a seed node as it binds on all local addresses on a fixed port (4040,
219	on the resulting addresses.	256	customary for aemp).
220		257
221	initialise_node "localhost:4044";	258	# use the aemp commandline utility
		259	# aemp profile seed nodeid anon/ binds '*:4040'
		260
		261	# then use it
		262	configure profile => "seed";
		263
		264	# or simply use aemp from the shell again:
		265	# aemp run profile seed
		266
		267	# or provide a nicer-to-remember nodeid
		268	# aemp run profile seed nodeid "$(hostname)"
222		269
223	=item $SELF	270	=item $SELF
224		271
225	Contains the current port id while executing C<rcv> callbacks or C<psub>	272	Contains the current port id while executing C<rcv> callbacks or C<psub>
226	blocks.	273	blocks.
…		…
336	msg1 => sub { ... },	383	msg1 => sub { ... },
337	...	384	...
338	;	385	;
339		386
340	Example: temporarily register a rcv callback for a tag matching some port	387	Example: temporarily register a rcv callback for a tag matching some port
341	(e.g. for a rpc reply) and unregister it after a message was received.	388	(e.g. for an rpc reply) and unregister it after a message was received.
342		389
343	rcv $port, $otherport => sub {	390	rcv $port, $otherport => sub {
344	my @reply = @_;	391	my @reply = @_;
345		392
346	rcv $SELF, $otherport;	393	rcv $SELF, $otherport;
…		…
348		395
349	=cut	396	=cut
350		397
351	sub rcv($@) {	398	sub rcv($@) {
352	my $port = shift;	399	my $port = shift;
353	my ($noderef, $portid) = split /#/, $port, 2;	400	my ($nodeid, $portid) = split /#/, $port, 2;
354		401
355	$NODE{$noderef} == $NODE{""}	402	$NODE{$nodeid} == $NODE{""}
356	or Carp::croak "$port: rcv can only be called on local ports, caught";	403	or Carp::croak "$port: rcv can only be called on local ports, caught";
357		404
358	while (@_) {	405	while (@_) {
359	if (ref $_[0]) {	406	if (ref $_[0]) {
360	if (my $self = $PORT_DATA{$portid}) {	407	if (my $self = $PORT_DATA{$portid}) {
361	"AnyEvent::MP::Port" eq ref $self	408	"AnyEvent::MP::Port" eq ref $self
362	or Carp::croak "$port: rcv can only be called on message matching ports, caught";	409	or Carp::croak "$port: rcv can only be called on message matching ports, caught";
363		410
364	$self->[2] = shift;	411	$self->[0] = shift;
365	} else {	412	} else {
366	my $cb = shift;	413	my $cb = shift;
367	$PORT{$portid} = sub {	414	$PORT{$portid} = sub {
368	local $SELF = $port;	415	local $SELF = $port;
369	eval { &$cb }; _self_die if $@;	416	eval { &$cb }; _self_die if $@;
370	};	417	};
371	}	418	}
372	} elsif (defined $_[0]) {	419	} elsif (defined $_[0]) {
373	my $self = $PORT_DATA{$portid} \|\|= do {	420	my $self = $PORT_DATA{$portid} \|\|= do {
374	my $self = bless [$PORT{$port} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";	421	my $self = bless [$PORT{$portid} \|\| sub { }, { }, $port], "AnyEvent::MP::Port";
375		422
376	$PORT{$portid} = sub {	423	$PORT{$portid} = sub {
377	local $SELF = $port;	424	local $SELF = $port;
378		425
379	if (my $cb = $self->[1]{$_[0]}) {	426	if (my $cb = $self->[1]{$_[0]}) {
…		…
401	}	448	}
402		449
403	$port	450	$port
404	}	451	}
405		452
		453	=item peval $port, $coderef[, @args]
		454
		455	Evaluates the given C<$codref> within the contetx of C<$port>, that is,
		456	when the code throews an exception the C<$port> will be killed.
		457
		458	Any remaining args will be passed to the callback. Any return values will
		459	be returned to the caller.
		460
		461	This is useful when you temporarily want to execute code in the context of
		462	a port.
		463
		464	Example: create a port and run some initialisation code in it's context.
		465
		466	my $port = port { ... };
		467
		468	peval $port, sub {
		469	init
		470	or die "unable to init";
		471	};
		472
		473	=cut
		474
		475	sub peval($$) {
		476	local $SELF = shift;
		477	my $cb = shift;
		478
		479	if (wantarray) {
		480	my @res = eval { &$cb };
		481	_self_die if $@;
		482	@res
		483	} else {
		484	my $res = eval { &$cb };
		485	_self_die if $@;
		486	$res
		487	}
		488	}
		489
406	=item $closure = psub { BLOCK }	490	=item $closure = psub { BLOCK }
407		491
408	Remembers C<$SELF> and creates a closure out of the BLOCK. When the	492	Remembers C<$SELF> and creates a closure out of the BLOCK. When the
409	closure is executed, sets up the environment in the same way as in C<rcv>	493	closure is executed, sets up the environment in the same way as in C<rcv>
410	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.	494	callbacks, i.e. runtime errors will cause the port to get C<kil>ed.
		495
		496	The effect is basically as if it returned C<< sub { peval $SELF, sub {
		497	BLOCK } } >>.
411		498
412	This is useful when you register callbacks from C<rcv> callbacks:	499	This is useful when you register callbacks from C<rcv> callbacks:
413		500
414	rcv delayed_reply => sub {	501	rcv delayed_reply => sub {
415	my ($delay, @reply) = @_;	502	my ($delay, @reply) = @_;
…		…
451		538
452	Monitor the given port and do something when the port is killed or	539	Monitor the given port and do something when the port is killed or
453	messages to it were lost, and optionally return a guard that can be used	540	messages to it were lost, and optionally return a guard that can be used
454	to stop monitoring again.	541	to stop monitoring again.
455		542
		543	In the first form (callback), the callback is simply called with any
		544	number of C<@reason> elements (no @reason means that the port was deleted
		545	"normally"). Note also that I<< the callback B<must> never die >>, so use
		546	C<eval> if unsure.
		547
		548	In the second form (another port given), the other port (C<$rcvport>)
		549	will be C<kil>'ed with C<@reason>, if a @reason was specified, i.e. on
		550	"normal" kils nothing happens, while under all other conditions, the other
		551	port is killed with the same reason.
		552
		553	The third form (kill self) is the same as the second form, except that
		554	C<$rvport> defaults to C<$SELF>.
		555
		556	In the last form (message), a message of the form C<@msg, @reason> will be
		557	C<snd>.
		558
		559	Monitoring-actions are one-shot: once messages are lost (and a monitoring
		560	alert was raised), they are removed and will not trigger again.
		561
		562	As a rule of thumb, monitoring requests should always monitor a port from
		563	a local port (or callback). The reason is that kill messages might get
		564	lost, just like any other message. Another less obvious reason is that
		565	even monitoring requests can get lost (for example, when the connection
		566	to the other node goes down permanently). When monitoring a port locally
		567	these problems do not exist.
		568
456	C<mon> effectively guarantees that, in the absence of hardware failures,	569	C<mon> effectively guarantees that, in the absence of hardware failures,
457	after starting the monitor, either all messages sent to the port will	570	after starting the monitor, either all messages sent to the port will
458	arrive, or the monitoring action will be invoked after possible message	571	arrive, or the monitoring action will be invoked after possible message
459	loss has been detected. No messages will be lost "in between" (after	572	loss has been detected. No messages will be lost "in between" (after
460	the first lost message no further messages will be received by the	573	the first lost message no further messages will be received by the
461	port). After the monitoring action was invoked, further messages might get	574	port). After the monitoring action was invoked, further messages might get
462	delivered again.	575	delivered again.
463		576
464	Note that monitoring-actions are one-shot: once messages are lost (and a	577	Inter-host-connection timeouts and monitoring depend on the transport
465	monitoring alert was raised), they are removed and will not trigger again.	578	used. The only transport currently implemented is TCP, and AnyEvent::MP
		579	relies on TCP to detect node-downs (this can take 10-15 minutes on a
		580	non-idle connection, and usually around two hours for idle connections).
466		581
467	In the first form (callback), the callback is simply called with any	582	This means that monitoring is good for program errors and cleaning up
468	number of C<@reason> elements (no @reason means that the port was deleted	583	stuff eventually, but they are no replacement for a timeout when you need
469	"normally"). Note also that I<< the callback B<must> never die >>, so use	584	to ensure some maximum latency.
470	C<eval> if unsure.
471
472	In the second form (another port given), the other port (C<$rcvport>)
473	will be C<kil>'ed with C<@reason>, iff a @reason was specified, i.e. on
474	"normal" kils nothing happens, while under all other conditions, the other
475	port is killed with the same reason.
476
477	The third form (kill self) is the same as the second form, except that
478	C<$rvport> defaults to C<$SELF>.
479
480	In the last form (message), a message of the form C<@msg, @reason> will be
481	C<snd>.
482
483	As a rule of thumb, monitoring requests should always monitor a port from
484	a local port (or callback). The reason is that kill messages might get
485	lost, just like any other message. Another less obvious reason is that
486	even monitoring requests can get lost (for exmaple, when the connection
487	to the other node goes down permanently). When monitoring a port locally
488	these problems do not exist.
489		585
490	Example: call a given callback when C<$port> is killed.	586	Example: call a given callback when C<$port> is killed.
491		587
492	mon $port, sub { warn "port died because of <@_>\n" };	588	mon $port, sub { warn "port died because of <@_>\n" };
493		589
…		…
500	mon $port, $self => "restart";	596	mon $port, $self => "restart";
501		597
502	=cut	598	=cut
503		599
504	sub mon {	600	sub mon {
505	my ($noderef, $port) = split /#/, shift, 2;	601	my ($nodeid, $port) = split /#/, shift, 2;
506		602
507	my $node = $NODE{$noderef} \|\| add_node $noderef;	603	my $node = $NODE{$nodeid} \|\| add_node $nodeid;
508		604
509	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';	605	my $cb = @_ ? shift : $SELF \|\| Carp::croak 'mon: called with one argument only, but $SELF not set,';
510		606
511	unless (ref $cb) {	607	unless (ref $cb) {
512	if (@_) {	608	if (@_) {
…		…
521	}	617	}
522		618
523	$node->monitor ($port, $cb);	619	$node->monitor ($port, $cb);
524		620
525	defined wantarray	621	defined wantarray
526	and AnyEvent::Util::guard { $node->unmonitor ($port, $cb) }	622	and ($cb += 0, AnyEvent::Util::guard { $node->unmonitor ($port, $cb) })
527	}	623	}
528		624
529	=item $guard = mon_guard $port, $ref, $ref...	625	=item $guard = mon_guard $port, $ref, $ref...
530		626
531	Monitors the given C<$port> and keeps the passed references. When the port	627	Monitors the given C<$port> and keeps the passed references. When the port
…		…
588	the package, then the package above the package and so on (e.g.	684	the package, then the package above the package and so on (e.g.
589	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function	685	C<MyApp::Chat::Server>, C<MyApp::Chat>, C<MyApp>) until the function
590	exists or it runs out of package names.	686	exists or it runs out of package names.
591		687
592	The init function is then called with the newly-created port as context	688	The init function is then called with the newly-created port as context
593	object (C<$SELF>) and the C<@initdata> values as arguments.	689	object (C<$SELF>) and the C<@initdata> values as arguments. It I<must>
		690	call one of the C<rcv> functions to set callbacks on C<$SELF>, otherwise
		691	the port might not get created.
594		692
595	A common idiom is to pass a local port, immediately monitor the spawned	693	A common idiom is to pass a local port, immediately monitor the spawned
596	port, and in the remote init function, immediately monitor the passed	694	port, and in the remote init function, immediately monitor the passed
597	local port. This two-way monitoring ensures that both ports get cleaned up	695	local port. This two-way monitoring ensures that both ports get cleaned up
598	when there is a problem.	696	when there is a problem.
599		697
		698	C<spawn> guarantees that the C<$initfunc> has no visible effects on the
		699	caller before C<spawn> returns (by delaying invocation when spawn is
		700	called for the local node).
		701
600	Example: spawn a chat server port on C<$othernode>.	702	Example: spawn a chat server port on C<$othernode>.
601		703
602	# this node, executed from within a port context:	704	# this node, executed from within a port context:
603	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;	705	my $server = spawn $othernode, "MyApp::Chat::Server::connect", $SELF;
604	mon $server;	706	mon $server;
…		…
618		720
619	sub _spawn {	721	sub _spawn {
620	my $port = shift;	722	my $port = shift;
621	my $init = shift;	723	my $init = shift;
622		724
		725	# rcv will create the actual port
623	local $SELF = "$NODE#$port";	726	local $SELF = "$NODE#$port";
624	eval {	727	eval {
625	&{ load_func $init }	728	&{ load_func $init }
626	};	729	};
627	_self_die if $@;	730	_self_die if $@;
628	}	731	}
629		732
630	sub spawn(@) {	733	sub spawn(@) {
631	my ($noderef, undef) = split /#/, shift, 2;	734	my ($nodeid, undef) = split /#/, shift, 2;
632		735
633	my $id = "$RUNIQ." . $ID++;	736	my $id = "$RUNIQ." . $ID++;
634		737
635	$_[0] =~ /::/	738	$_[0] =~ /::/
636	or Carp::croak "spawn init function must be a fully-qualified name, caught";	739	or Carp::croak "spawn init function must be a fully-qualified name, caught";
637		740
638	snd_to_func $noderef, "AnyEvent::MP::_spawn" => $id, @_;	741	snd_to_func $nodeid, "AnyEvent::MP::_spawn" => $id, @_;
639		742
640	"$noderef#$id"	743	"$nodeid#$id"
641	}	744	}
642		745
643	=item after $timeout, @msg	746	=item after $timeout, @msg
644		747
645	=item after $timeout, $callback	748	=item after $timeout, $callback
…		…
662	? $action[0]()	765	? $action[0]()
663	: snd @action;	766	: snd @action;
664	};	767	};
665	}	768	}
666		769
		770	=item cal $port, @msg, $callback[, $timeout]
		771
		772	A simple form of RPC - sends a message to the given C<$port> with the
		773	given contents (C<@msg>), but adds a reply port to the message.
		774
		775	The reply port is created temporarily just for the purpose of receiving
		776	the reply, and will be C<kil>ed when no longer needed.
		777
		778	A reply message sent to the port is passed to the C<$callback> as-is.
		779
		780	If an optional time-out (in seconds) is given and it is not C<undef>,
		781	then the callback will be called without any arguments after the time-out
		782	elapsed and the port is C<kil>ed.
		783
		784	If no time-out is given (or it is C<undef>), then the local port will
		785	monitor the remote port instead, so it eventually gets cleaned-up.
		786
		787	Currently this function returns the temporary port, but this "feature"
		788	might go in future versions unless you can make a convincing case that
		789	this is indeed useful for something.
		790
		791	=cut
		792
		793	sub cal(@) {
		794	my $timeout = ref $_[-1] ? undef : pop;
		795	my $cb = pop;
		796
		797	my $port = port {
		798	undef $timeout;
		799	kil $SELF;
		800	&$cb;
		801	};
		802
		803	if (defined $timeout) {
		804	$timeout = AE::timer $timeout, 0, sub {
		805	undef $timeout;
		806	kil $port;
		807	$cb->();
		808	};
		809	} else {
		810	mon $_[0], sub {
		811	kil $port;
		812	$cb->();
		813	};
		814	}
		815
		816	push @_, $port;
		817	&snd;
		818
		819	$port
		820	}
		821
667	=back	822	=back
668		823
669	=head1 AnyEvent::MP vs. Distributed Erlang	824	=head1 AnyEvent::MP vs. Distributed Erlang
670		825
671	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node	826	AnyEvent::MP got lots of its ideas from distributed Erlang (Erlang node
672	== aemp node, Erlang process == aemp port), so many of the documents and	827	== aemp node, Erlang process == aemp port), so many of the documents and
673	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a	828	programming techniques employed by Erlang apply to AnyEvent::MP. Here is a
674	sample:	829	sample:
675		830
676	http://www.Erlang.se/doc/programming_rules.shtml	831	http://www.erlang.se/doc/programming_rules.shtml
677	http://Erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4	832	http://erlang.org/doc/getting_started/part_frame.html # chapters 3 and 4
678	http://Erlang.org/download/Erlang-book-part1.pdf # chapters 5 and 6	833	http://erlang.org/download/erlang-book-part1.pdf # chapters 5 and 6
679	http://Erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5	834	http://erlang.org/download/armstrong_thesis_2003.pdf # chapters 4 and 5
680		835
681	Despite the similarities, there are also some important differences:	836	Despite the similarities, there are also some important differences:
682		837
683	=over 4	838	=over 4
684		839
685	=item * Node IDs are arbitrary strings in AEMP.	840	=item * Node IDs are arbitrary strings in AEMP.
686		841
687	Erlang relies on special naming and DNS to work everywhere in the same	842	Erlang relies on special naming and DNS to work everywhere in the same
688	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by	843	way. AEMP relies on each node somehow knowing its own address(es) (e.g. by
689	configuraiton or DNS), but will otherwise discover other odes itself.	844	configuration or DNS), and possibly the addresses of some seed nodes, but
		845	will otherwise discover other nodes (and their IDs) itself.
690		846
691	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP	847	=item * Erlang has a "remote ports are like local ports" philosophy, AEMP
692	uses "local ports are like remote ports".	848	uses "local ports are like remote ports".
693		849
694	The failure modes for local ports are quite different (runtime errors	850	The failure modes for local ports are quite different (runtime errors
…		…
707		863
708	Erlang uses processes that selectively receive messages, and therefore	864	Erlang uses processes that selectively receive messages, and therefore
709	needs a queue. AEMP is event based, queuing messages would serve no	865	needs a queue. AEMP is event based, queuing messages would serve no
710	useful purpose. For the same reason the pattern-matching abilities of	866	useful purpose. For the same reason the pattern-matching abilities of
711	AnyEvent::MP are more limited, as there is little need to be able to	867	AnyEvent::MP are more limited, as there is little need to be able to
712	filter messages without dequeing them.	868	filter messages without dequeuing them.
713		869
714	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).	870	(But see L<Coro::MP> for a more Erlang-like process model on top of AEMP).
715		871
716	=item * Erlang sends are synchronous, AEMP sends are asynchronous.	872	=item * Erlang sends are synchronous, AEMP sends are asynchronous.
717		873
…		…
719	so does not need a queue that can overflow). AEMP sends are immediate,	875	so does not need a queue that can overflow). AEMP sends are immediate,
720	connection establishment is handled in the background.	876	connection establishment is handled in the background.
721		877
722	=item * Erlang suffers from silent message loss, AEMP does not.	878	=item * Erlang suffers from silent message loss, AEMP does not.
723		879
724	Erlang makes few guarantees on messages delivery - messages can get lost	880	Erlang implements few guarantees on messages delivery - messages can get
725	without any of the processes realising it (i.e. you send messages a, b,	881	lost without any of the processes realising it (i.e. you send messages a,
726	and c, and the other side only receives messages a and c).	882	b, and c, and the other side only receives messages a and c).
727		883
728	AEMP guarantees correct ordering, and the guarantee that after one message	884	AEMP guarantees correct ordering, and the guarantee that after one message
729	is lost, all following ones sent to the same port are lost as well, until	885	is lost, all following ones sent to the same port are lost as well, until
730	monitoring raises an error, so there are no silent "holes" in the message	886	monitoring raises an error, so there are no silent "holes" in the message
731	sequence.	887	sequence.
…		…
823	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.	979	L<AnyEvent::MP::Kernel> - more, lower-level, stuff.
824		980
825	L<AnyEvent::MP::Global> - network maintainance and port groups, to find	981	L<AnyEvent::MP::Global> - network maintainance and port groups, to find
826	your applications.	982	your applications.
827		983
		984	L<AnyEvent::MP::DataConn> - establish data connections between nodes.
		985
		986	L<AnyEvent::MP::LogCatcher> - simple service to display log messages from
		987	all nodes.
		988
828	L<AnyEvent>.	989	L<AnyEvent>.
829		990
830	=head1 AUTHOR	991	=head1 AUTHOR
831		992
832	Marc Lehmann <schmorp@schmorp.de>	993	Marc Lehmann <schmorp@schmorp.de>

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Comparing AnyEvent-MP/MP.pm (file contents): Revision 1.71 by root, Sun Aug 30 19:52:56 2009 UTC vs. Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC

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Comparing AnyEvent-MP/MP.pm (file contents):
Revision 1.71 by root, Sun Aug 30 19:52:56 2009 UTC vs.
Revision 1.106 by root, Wed Dec 9 14:00:49 2009 UTC